This project is aimed at elucidating the host immune response(s) to malignant melanoma, and the role these response(s) play in the progression of tumor growth and metastatic spread. Our preliminary results indicate that various murine melanomas (of spontaneous, ultraviolet light induced, and chemically induced origin) share common cell surface antigens which are capable of eliciting a tumor rejection response. These antigens appear to have specificity restricted to melanoma cells based on immunization protocols with other neoplastic cell lines. Initial purification attempts have shown that aqueous butanol solubilizes this antigen(s) quantitatively from the melanoma cell surface.